[Technical Field]
[0001] The present invention relates to a turbocharger which includes a turbine and a compressor.
[Background Art]
[0002] A turbocharger including a turbine and a compressor has been widely used as a supercharger
for improving a performance of an internal combustion engine. In the turbocharger,
a turbine wheel (turbine impeller) constituting the turbine and a compressor wheel
(compressor impeller) constituting the compressor are connected to each other by a
rotating shaft. An exhaust gas from the internal combustion engine is fed into the
turbine side. The exhaust gas thus fed rotates the turbine wheel and thereby rotates
the compressor wheel. Air is forced to flow into a cylinder of the internal combustion
engine by the rotation of the compressor wheel, whereby a gas pressure inside the
cylinder is raised and virtual displacement is increased.
[0003] The above-described turbocharger needs to rotate and drive the turbine and the compressor
at a high speed. As a consequence, the rotating shaft is also rotated at a high speed.
It is therefore extremely important to ensure lubrication between the rotating shaft
and a housing that houses the rotating shaft. PTL 1 cited below proposes a bearing
device for a turbocharger, which is intended to remove foreign matter in oil that
serves as a lubricant.
[0004] In the bearing device of PTL 1, a detour is provided in the vicinity of an oil inlet
inside a housing and a filter is disposed in the detour. Foreign matter in the oil
is removed by the filter, and the oil from which the foreign matter is removed is
then supplied from the inlet to rolling bearings.
[Citation List]
[Patent Literature]
[0005] [PTL 1] Japanese Patent Application Laid-open Publication No.
2010-96120
[Summary of Invention]
[Technical Problem]
[0006] In the related art described above, the rolling bearings hold the rotating shaft.
Accordingly, a particular problem seems not to occur even when the oil is supplied
through the detour where the filter is disposed. On the other hand, the application
of the above-described related art without alteration is not preferable when the type
of the bearing is changed to a fluid bearing which is a plain bearing.
[0007] A fluid bearing includes a bearing member such as a semi-floating metal disposed
between a rotating shaft and a housing, and is designed to form an oil film by forcing
oil into the clearance between the housing and the bearing member at a high pressure,
and to form an oil film by forcing the oil into the clearance between the rotating
shaft and the bearing member at a high pressure . The formation of the oil films between
these components as described above enables the rotating shaft to rotate at a high
speed.
[0008] If a filter as in the related art is provided for such a fluid bearing, the filter
causes a reduction of pressure, which may complicate the formation of the oil films
between the components . In order to supply the oil at a sufficient pressure to the
fluid bearing, a supply pressure of the oil has to be increased or a screen of the
filter has to be made coarse. Nonetheless, the installation of a specific device for
increasing the supply pressure of the oil should be avoided. For this reason, the
increase range in the supply pressure of the oil is limited. On the other hand, if
the screen of the filter is made coarse, then foreign matter is more likely to flow
into the fluid bearing side. In this context, the filter method is not always effective
in order to remove the foreign matter from the oil inside the turbocharger that employs
the fluid bearing. In addition, if the filter method is employed, it is necessary
to conduct maintenance work such as the replacement or cleaning of the filter due
to the necessity of disposing the filter in an oil supply path.
[0009] In the case of the fluid bearing, it is not preferable to provide the filter on the
oil supply path in the fluid bearing, but the necessity of removing the foreign matter
from the oil is higher than in the case of the rolling bearing. The fluid bearing
is configured to exert the function as the bearing by use of the oil films formed
between the components . Accordingly, each clearance between the components is so
small that the entry of even minute foreign matter may cause a trouble. To be more
precise, the minute foreign matter moving between the components may damage opposed
surfaces of the components or the minute foreign matter stuck between the components
may block a flow of the oil between the components. The occurrence of these phenomena
may lead to seizure due to the shortage of the oil or the locking of the rotating
shaft, and may cause a reduction in supercharging pressure or the occurrence of abnormal
noise from the turbocharger.
[0010] The present invention has been made in view of the above-mentioned problems. An object
of the present invention is to provide a turbocharger which employs a fluid bearing
to support a rotating shaft that connects a turbine and a compressor to each other,
and is capable of minimizing the entry of minute foreign matter into the fluid bearing
without blocking a function of the fluid bearing.
[0011] WO2011/058627 and
EP2500544A disclose a turbocharger including: a turbine wheel constituting a turbine; a compressor
wheel constituting a compressor; a rotating shaft connecting the turbine wheel and
the compressor wheel to each other; a housing which houses at least the rotating shaft;
and a semi-floating fluid bearing between the rotating shaft and the housing. The
semi-floating bearing is provided with a supply opening configured to supply oil to
an inner bearing section formed between the semi-floating bearing and the rotating
shaft. The turbocharger is provided with an oil supply path extending from inside
of the housing to the supply opening and configured to feed the oil to be supplied
to the inner bearing section. In addition, the oil supply path is provided with a
removal section configured to change a flowing direction of the oil supplied from
an upstream side to separate minute foreign matter in the oil. The turbocharger is
provided with a collecting section configured to collect the minute foreign matter
separated by the removal section so as to prevent the minute foreign matter from mixing
again with the oil flowing toward the supply opening.
EP2500544A discloses a turbocharger according to the preamble of claim 1.
[0012] The invention is in the turbocharger of claim 1. It comprises a housing, a turbine
wheel constituting a turbine; a compressor wheel constituting a compressor; a rotating
shaft connecting the turbine wheel and the compressor wheel to each other, the housing
housings at least the rotating shaft; and a semi-floating metal bearing also housed
in the housing, forming a fluid bearing between the rotating shaft and the housing,
and rotatably supporting the rotating shaft, wherein the semi-floating metal bearing
is fixed to the housing by a pin, an oil reservoir space is formed between the housing
and the semi floating metal bearing to temporarily retain oil, the housing is provided
with an upstream side first supply opening configured to supply oil to the oil reservoir
space, and the semi-floating metal bearing is provided with a second supply opening
configured to supply oil in the oil reservoir space to an inner bearing section formed
between the semi-floating metal bearing and the rotating shaft, an oil supply path
(FL) extending from inside of the housing to the second supply opening via the first
supply opening is formed to feed oil to be supplied to the inner bearing section and
is provided with a removal section configured to change a flowing direction of the
oil supplied from an upstream side to separate minute foreign matter in the oil. It
is characterized in that the first supply opening and the second supply opening are
located at different positions without being overlapped to each other in an axial
direction of the rotating shaft, the removal section comprises a separation wall surface
formed in an outer peripheral surface of the semi-floating metal bearing, and is opposed
to the first supply opening and to a flow of the oil supplied from the upstream side,
an outer diameter of the outer peripheral surface of the semi-floating metal bearing
is constant from a position opposed to the first supply opening to the second supply
opening and an inner diameter of a housing inner wall is constant from the first supply
opening to a position opposed to the second supply opening; and a collecting section
(TA, SA) is provided to collect the minute foreign matter (CT) separated by the separation
wall surface so as to prevent the minute foreign matter (CT) from mixing again with
the oil flowing toward the second supply opening.
[0013] In the turbocharger, the collecting section may include: a retaining region configured
to retain the minute foreign matter separated by the removal section, so as to prevent
the minute foreign matter from mixing again with the oil flowing toward the supply
opening; and a conveyance path configured to move the minute foreign matter, separated
by the removal section, from the removal section to the retaining region. The conveyance
path may be joined to the removal section at a position different from a main flow
path on which the oil flows from the removal section toward the supply opening.
[0014] In the turbocharger, an oil reservoir space configured to temporarily retain the
oil may be formed between the housing and the semi-floating bearing. In addition,
the retaining region and the conveyance path may be formed in the oil reservoir space.
[0015] In the turbocharger, the retaining region may be formed below the removal section
and the supply opening.
[0016] In the turbocharger, a guide wall surface configured to guide the minute foreign
matter to the conveyance path may be formed between the removal section and the supply
opening.
[0017] The above-mentioned configurations can be combined with one another unless the configurations
are not technically incompatible with one another. When the configurations are combined,
their combinations can exert the operations and effects that are intrinsic to the
respective configurations.
[Advantageous Effects of Invention]
[0018] According to the present invention, it is possible to provide a turbocharger which
employs a fluid bearing to support a rotating shaft that connects a turbine and a
compressor to each other, and is capable of minimizing the entry of minute foreign
matter into the fluid bearing without blocking a function of the fluid bearing.
[Brief Description of Drawings]
[0019]
[Fig. 1]
Fig. 1 is a schematic cross-sectional view of a turbocharger which is an embodiment
of the present invention.
[Fig. 2]
Fig. 2 is an enlarged cross-sectional view enlarging a bearing section in Fig. 1.
[Fig. 3]
Fig. 3 is an enlarged cross-sectional view showing a first modified example of the
embodiment depicted in Fig. 2, not part of the invention.
[Fig. 4]
Fig. 4 is an enlarged cross-sectional view showing a second modified example of the
embodiment depicted in Fig. 2.
[Fig. 5]
Fig. 5 is a vertical sectional view showing an A-A cross section in Fig. 4.
[Fig. 6]
Fig. 6 is an enlarged cross-sectional view showing a third modified example of the
embodiment depicted in Fig. 2, not part of the invention.
[Fig. 7]
Fig. 7 is an enlarged cross-sectional view showing a fourth modified example of the
embodiment depicted in Fig. 2, not part of the invention.
[Fig. 8]
Fig. 8 is a vertical sectional view showing a B-B cross section in Fig. 7, not part
of the invention.
[Description of Embodiments]
[0020] An embodiment of the present invention will be described below with reference to
the accompanying drawings . To make the descriptions understood easily, the same constituents
in the drawings are denoted by the same reference numerals as much as possible and
overlapped descriptions will be omitted.
[0021] A turbocharger representing an embodiment of the present invention will be described
with reference to Fig. 1. Fig. 1 is a schematic cross-sectional view of a turbocharger
TC which is the embodiment of the present invention. As shown in Fig. 1, the turbocharger
TC of the embodiment includes a bearing housing 2, a turbine 3 provided with a turbine
wheel (turbine impeller) 31, a compressor 4 provided with a compressor wheel (compressor
impeller) 41, a rotating shaft 5, and a semi-floating metal 6.
[0022] The turbine wheel 31 is a key component that constitutes the turbine 3, and is housed
in a turbine housing 32. The compressor wheel 41 is a key component that constitutes
the compressor 4, and is housed in a compressor housing 42. The turbine wheel 31 and
the compressor wheel 41 are connected to each other by the rotating shaft 5. The rotating
shaft 5 is rotatably held by the semi-floating metal 6 interposed between the bearing
housing 2 and the rotating shaft 5.
[0023] The turbine housing 32 includes a turbine side scroll chamber which is not clearly
shown in Fig. 1. The turbine side scroll chamber is a chamber which houses the turbine
wheel 31. The turbine side scroll chamber is provided with an inlet port for supplying
an exhaust gas from an internal combustion engine to the inside of the chamber, and
an outlet port for discharging the supplied exhaust gas. The turbine wheel 31 is rotated
by the exhaust gas supplied from the inlet port, whereby the rotating shaft 5 is rotated
and driven.
[0024] The compressor housing 42 includes a compressor side scroll chamber which is not
clearly shown in Fig. 1. The compressor side scroll chamber is a chamber which houses
the compressor wheel 41. The compressor side scroll chamber is provided with an inlet
port for supplying air to the inside of the chamber, and an outlet port for feeding
the supplied air to the internal combustion engine. The compressor wheel 41 is rotated
in response to the rotating shaft 5 that is rotated and driven. With the rotation
of the compressor wheel 41, the air is taken in from the inlet port and is compressed
inside the compressor side scroll chamber. The compressed air is fed from the outlet
port to the internal combustion engine.
[0025] The bearing housing 2 houses the semi-floating metal 6 which rotatably holds the
rotating shaft 5. The semi-floating metal 6 is a component which has a substantially
cylindrical shape. The semi-floating metal 6 is fixed to the bearing housing 2 by
use of a thrust pin 7. The semi-floating metal 6 is fixed to the bearing housing 2
in such a manner as to be movable in a radial direction of the semi-floating metal
6 but not to be movable or rotatable in its axial and rotational directions.
[0026] The semi-floating metal 6 is formed as a member having stepped shapes on both of
its inner and outer peripheral surfaces. The inner peripheral surface of the semi-floating
metal 6 includes: an inside small diameter portion 62a formed on one end; an inside
small diameter portion 63a formed on the other end; and an inside large diameter portion
61a formed at a central portion between the inside small diameter portion 62a and
the inside small diameter portion 63a. An inner diameter of the inside small diameter
portion 62a and an inner diameter of the inside small diameter portion 63a are formed
substantially equal to each other. The inside large diameter portion 61a is formed
to have an inner diameter which is larger than the inner diameters of the inside small
diameter portion 62a and the inside small diameter portion 63a.
[0027] The outer peripheral surface of the semi-floating metal 6 includes : an outside large
diameter portion 62b formed on one end; an outside large diameter portion 63b formed
on the other end; and an outside small diameter portion 61b formed at a central portion
between the outside large diameter portion 62b and the outside large diameter portion
63b. An outer diameter of the outside large diameter portion 62b and an outer diameter
of the outside large diameter portion 63b are formed substantially equal to each other.
The outside small diameter portion 61b is formed to have an outer diameter which is
smaller than the outer diameters of the outside large diameter portion 62b and the
outside large diameter portion 63b.
[0028] The rotating shaft 5 is inserted in the inner peripheral surface side of the semi-floating
metal 6. A small diameter portion 51, and large diameter portions 52 and 53 provided
in such a manner as to sandwich the small diameter portion 51, are formed at part
of the rotating shaft 5 that is inserted in the inner peripheral surface side of the
semi-floating metal 6. Each of the large diameter portions 52 and 53 is formed to
have an outer diameter which is larger than an outer diameter of the small diameter
portion 51. The large diameter portion 52 is located at a position opposed to the
inside small diameter portion 62a and the large diameter portion 53 is located at
a position opposed to the inside small diameter portion 63a. A clearance between the
large diameter portion 52 and the inside small diameter portion 62a is extremely small,
and an oil film is formed by forcing oil at a high pressure into the small clearance.
Similarly, a clearance between the large diameter portion 53 and the inside small
diameter portion 63a is extremely small, and an oil film is formed by forcing the
oil at the high pressure into the small clearance.
[0029] A diameter enlarged portion 5A is provided between the large diameter portion 52
of the rotating shaft 5 and the turbine wheel 31. The diameter enlarged portion 5A
is formed integrally with the rotating shaft 5 in such a manner as to be in intimate
contact with the large diameter portion 52. The oil forming the oil film by being
forced into the clearance between the large diameter portion 52 and the inside small
diameter portion 62a passes through a gap between the diameter enlarged portion 5A
and the semi-floating metal 6 as well as a gap between the diameter enlarged portion
5A and the bearing housing 2, and flows back to an oil pan which is not clearly shown
in the drawing.
[0030] A thrust cup member 5B is provided between the large diameter portion 53 of the rotating
shaft 5 and the compressor wheel 41. The thrust cup member 5B is fitted into the rotating
shaft 5 in such a manner as to be in intimate contact with the large diameter portion
53 . The oil forming the oil film by being forced into the clearance between the large
diameter portion 53 and the inside small diameter portion 63a passes through a gap
between the thrust cup member 5B and the semi-floating metal 6 as well as a gap between
the thrust cup member 5B and the bearing housing 2, and flows back to the oil pan
which is not clearly shown in the drawing.
[0031] As described above, the small diameter portion 51 is provided between the large diameter
portion 52 and the large diameter portion 53 of the rotating shaft 5. Meanwhile, the
inside large diameter portion 61a is provided between the inside small diameter portion
62a and the inside small diameter portion 63a of the semi-floating metal 6. Accordingly,
the small diameter portion 51 of the rotating shaft 5 and the inside large diameter
portion 61a of the semi-floating metal 6 are respectively arranged at such positions
to face each other, and an inside oil reservoir space 8a is thus formed.
[0032] A supply opening 61c is formed in the semi-floating metal 6 in order to supply the
oil to the inside oil reservoir space 8a. The supply opening 61c is formed penetrating
the semi-floating metal 6 from the inside large diameter portion 61a to the outside
small diameter portion 61b. In this embodiment, the supply opening 61c is formed in
such a manner as to be located on the opposite side of the rotating shaft 5 from the
thrust pin 7, or in other words, to be located above the rotating shaft 5 in Fig.
1.
[0033] Housing inner walls 21, 22, and 23 are formed at portions of the bearing housing
2 which the semi-floating metal 6 is housed in. The housing inner wall 22 and the
housing inner wall 23 are formed while interposing the housing inner wall 21 in between.
[0034] The housing inner wall 22 forms a circular cross section and a part of the cross
section is provided facing the outside large diameter portion 62b of the semi-floating
metal 6 while the rest of the cross section is provided facing the outside small diameter
portion 61b of the semi-floating metal 6. A clearance between the housing inner wall
22 and the outside large diameter portion 62b is extremely small, and an oil film
is formed by forcing the oil at the high pressure into the small clearance.
[0035] The housing inner wall 23 forms a circular cross section with the diameter equal
to that of the housing inner wall 22, and a part of the cross section is provided
facing the outside large diameter portion 63b of the semi-floating metal 6 while the
rest of the cross section is provided facing the outside small diameter portion 61b
of the semi-floating metal 6. A clearance between the housing inner wall 23 and the
outside large diameter portion 63b is extremely small, and an oil film is formed by
forcing the oil at the high pressure into the small clearance.
[0036] The housing inner wall 21 forms a circular cross section with the diameter larger
than those of the housing inner walls 22 and 23, and is provided at a position to
face the outside small diameter portion 61b of the semi-floating metal 6. As a consequence,
an outside oil reservoir space 8b is formed between the housing inner wall 21 and
the outside small diameter portion 61b.
[0037] A housing side supply opening 26 (an upstream side supply opening) for supplying
the oil to the outside oil reservoir space 8b is formed in the bearing housing 2.
An oil feed passage 25 is formed in the bearing housing 2 so as to communicate with
the housing side supply opening 26. The oil with the high pressure is supplied to
the oil feed passage 25, passed through the housing side supply opening 26, and supplied
to the outside oil reservoir space 8b.
[0038] The housing side supply opening 26 is formed at a position opposed to the outside
small diameter portion 61b of the semi-floating metal 6. The supply opening 61c formed
in the semi-floating metal 6 and the housing side supply opening 26 are formed in
different positions so as not to be opposed to each other. As a consequence, the oil
supplied to the outside oil reservoir space 8b hits the outside small diameter portion
61b of the semi-floating metal 6, whereby a flowing direction of the oil is changed
and the oil flows toward the supply opening 61c. The above-mentioned flow of the oil
forms an oil supply path FL which extends from the oil feed passage 25 to the inside
oil reservoir space 8a. In this embodiment, minute foreign matter contained in the
oil is prevented from going into the semi-floating metal 6 by utilizing the above-mentioned
change in the direction of the oil on the oil supply path FL.
[0039] Next, how the minute foreign matter is removed will be described in detail with
reference to Fig. 2. Fig. 2 is an enlarged cross-sectional view enlarging a bearing
section in Fig. 1. As shown in Fig. 2, the oil supplied from the oil feed passage
25 passes through the housing side supply opening 26 and is supplied to the outside
oil reservoir space 8b. Since the housing side supply opening 26 is opposed to the
outside small diameter portion 61b of the semi-floating metal 6, the oil supplied
from the housing side supply opening 26 to the outside oil reservoir space 8b hits
the outside small diameter portion 61b and its flowing direction is changed. Since
the outside oil reservoir space 8b is filled with the oil, a main flow of the oil,
in which most of the oil flows even though not forming a fast flow, flows toward the
supply opening 61c along the oil supply path FL.
[0040] Meanwhile, minute foreign matter CT contained in the oil taps into the flow of the
oil and is conveyed from the oil feed passage 25 to the outside oil reservoir space
8b through the housing side supply opening 26. As described previously, the flowing
direction of the oil supplied to the outside oil reservoir space 8b is changed substantially
at a right angle along the oil supply path FL. Here, the minute foreign matter CT
contained in the oil has a higher specific gravity than the oil. Accordingly, the
minute foreign matter CT does not follow the change in the flowing direction of the
oil but falls along the outer peripheral surface of the outside small diameter portion
61b by inertia. Hence, the minute foreign matter CT moves downward in Fig. 2 (in a
direction from the housing side supply opening 26 toward the thrust pin 7). The minute
foreign matter CT moving downward is retained in a lower part of the outside oil reservoir
space 8b.
[0041] As a result of applying the above-described configuration, a portion near an outlet
of the housing side supply opening 26, part of the outside small diameter portion
61b opposed to the housing side supply opening 26, and part of the outside oil reservoir
space 8b located in between collectively function as a removal section RA for separating
the minute foreign matter CT from the oil. Meanwhile, the lower part of the outside
oil reservoir space 8b functions as a retaining region SA which retains the minute
foreign matter CT separated from the oil, so as to prevent the minute foreign matter
CT from mixing again with the oil which flows toward the supply opening 61c. In the
meantime, the part of the outside oil reservoir space 8b joining the removal section
RA and the retaining region SA functions as a conveyance path TA, which causes the
minute foreign matter CT separated by the removal section RA to move from the removal
section RA to the retaining region SA. Accordingly, the retaining region SA and the
conveyance path TA function as a collecting section which collects the minute foreign
matter CT separated from the oil in the removal section RA, so as to prevent the minute
foreign matter CT from mixing again with the oil which flows toward the supply opening
61c.
[0042] As described above, in this embodiment and according to the invention, the oil supply
path FL is provided with the removal section RA which is configured to separate the
minute foreign matter CT in the oil by changing the flowing direction of the oil.
Thus, it is possible to remove the minute foreign matter CT in the oil without providing
a filter on the oil supply path FL. Since the minute foreign matter CT is separated
by changing the flowing direction of the oil without using the filter, a supply pressure
of the oil supplied to the fluid bearing is not reduced more than needed, and hence
the function of the fluid bearing is not blocked. Meanwhile, the minute foreign matter
CT separated from the oil is collected by the conveyance path TA and the retaining
region SA which serve as the collecting section, so as to prevent the minute foreign
matter CT from mixing again with the oil that flows toward the supply opening 61c
configured to supply the oil to a space (i.e., an inner bearing section) between the
large diameter portions 52 and 53 as well as the inside small diameter portions 62a
and 63a. Thus, it is possible to inhibit the minute foreign matter CT from mixing
again with the oil and flowing toward the inner bearing section.
[0043] As described above, in this embodiment, the retaining region SA which retains the
minute foreign matter CT separated from the oil by the removal section RA so as to
prevent the minute foreign matter CT from mixing again with the oil that flows toward
the supply opening 61c, and the conveyance path TA which causes the minute foreign
matter CT separated by the removal section RA to move from the removal section RA
to the retaining region SA, are formed collectively as the collecting section. As
shown in Fig. 2, the conveyance path TA is joined to the removal section RA at a position
which is different from the main flow path (a flow path along the arrow indicated
in Fig. 2 as the oil feed passage) on which the oil flows from the removal section
RA toward the supply opening 61c. Specifically, in the example shown in Fig. 2, the
main flow path extends from the left side of the removal section RA in the drawing,
while the conveyance path TA extends from a portion below the removal section RA in
the drawing.
[0044] The retaining region SA which retains the minute foreign matter CT so as to prevent
the minute foreign matter CT from mixing again with the oil flowing toward the supply
opening 61c, and the conveyance path TA which causes the minute foreign matter CT
to move from the removal section RA to the retaining region SA, are formed as described
above. Accordingly, it is possible to locate the removal section RA securely away
from the retaining region SA and thereby to surely retain the removed minute foreign
matter CT. In addition, the conveyance path TA is joined to the removal section RA
at the position different from the main flow path on which the oil flows from the
removal section RA toward the supply opening 61c. Thus, it is possible to guide the
minute foreign matter CT, which has been separated from the oil flowing on the main
flow by the removal section RA, to the retaining region SA through the conveyance
path TA without returning the minute foreign matter CT to the main flow path side.
[0045] Moreover, in this embodiment and according to the invention, the outside oil reservoir
space 8b configured to temporarily retain the oil is formed between the bearing housing
2 and the semi-floating metal 6. In addition, the retaining region SA and the conveyance
path TA are formed in the outside oil reservoir space 8b.
[0046] Since the conveyance path TA and the retaining region SA are formed in the outside
oil reservoir space 8b as described above, it is possible to downsize the turbocharger
TC and to form the conveyance path TA and the retaining region SA closer to the supply
opening 61c. As a consequence, the removal section RA can also be located closer to
the supply opening 61c, so that the minute foreign matter CT can be separated from
the oil at a position closer to the supply opening 61c. Since the minute foreign matter
CT is separated from the oil at the position closer to the supply opening 61c, it
is possible to minimize a possibility of the entry of minute foreign matter CT which
occurs between the removal section RA and the supply opening 61c.
[0047] In this embodiment, the retaining region SA is formed below the removal section RA
and the supply opening 61c. By locating the retaining region SA below the removal
section RA, it is possible to achieve the configuration to cause the minute foreign
matter CT separated by the removal section RA to fall by its own weight along the
outer peripheral surface of the outside small diameter portion 61b, and to surely
gather in the retaining region SA. In addition, although the retaining region SA is
formed in the outside oil reservoir space 8b, the minute foreign matter CT retained
in the retaining region SA can even more surely be inhibited from moving toward the
supply opening 61c since the retaining region SA is located below the supply opening
61c.
[0048] In this embodiment and according to the invention, the removal section RA includes
a separation wall surface which is opposed to the flow of the oil supplied from the
upstream side. Here, a portion of the outside small diameter portion 61b in the removal
section RA, which is the portion of the outer peripheral surface of the semi-floating
metal 6 opposed to the housing side supply opening 26, corresponds to the separation
wall surface in the above-described embodiment.
[0049] As described above, the removal section RA has the separation wall surface and the
separation wall surface is located opposite the flow of the oil supplied from the
upstream side. Accordingly, the entire flow of the oil supplied form the upstream
side can surely be changed.
[0050] Furthermore, since the separation wall surface is formed on the outer peripheral
surface of the semi-floating metal 6, it is possible to form the smaller turbocharger
TC as compared to the case of additionally providing an independent wall surface,
and moreover, to separate the minute foreign matter CT from the oil at the position
closer to the supply opening 61c.
[0051] In this embodiment, according to the invention, the separation wall surface is formed
by locating the housing side supply opening 26 and the supply opening 61c at different
positions. Since the separation wall surface is formed by locating the housing side
supply opening 26 and the supply opening 61c at the different positions as described
above, the separation wall can be formed easily and surely on the outer peripheral
surface of the semi-floating metal 6.
[0052] Next, a first modified example (not claimed) of the embodiment will be described
with reference to Fig. 3. Fig. 3 is an enlarged cross-sectional view showing the first
modified example of the invention depicted in Fig. 2. The modified example shown in
Fig. 3 uses a semi-floating metal 6L which is prepared by providing the semi-floating
metal 6 with a guide protrusion 61d and a guide recess 61e.
[0053] The guide protrusion 61d is formed in the removal section RA. To be more precise,
the guide protrusion 61d is provided in the vicinity of the supply opening 61c and
beside the housing side supply opening 26. A surface of the guide protrusion 61d directed
to the housing side supply opening 26 forms a guide wall surface 61da. Even if the
minute foreign matter CT tries to flow toward the supply opening 61c, the minute foreign
matter CT is blocked by the guide wall surface 61da and is guided toward the conveyance
path TA.
[0054] The guide recess 61e is formed in the removal section RA. To be more precise, the
guide recess 61e is provided in the vicinity of the supply opening 61c and beside
the housing side supply opening 26, and is adjacent to the housing side supply opening
26 side of the guide protrusion 61d. A surface of the guide recess 61e directed to
the housing side supply opening 26 forms a guide wall surface 61ea. Even if the minute
foreign matter CT tries to flow toward the supply opening 61c, the minute foreign
matter CT is blocked by the guide wall surface 61ea and is guided toward the conveyance
path TA.
[0055] Although both the guide protrusion 61d and the guide recess 61e are provided in this
example, it is possible to provide any one of the guide protrusion 61d and the guide
recess 61e instead.
[0056] Next, a second modified example of the embodiment will be described with reference
to Fig. 4 and Fig. 5. Fig. 4 is an enlarged cross-sectional view showing the second
modified example of the embodiment depicted in Fig. 2. Fig. 5 is a cross-sectional
view showing an A-A cross section in Fig. 4. The modified example shown in Fig. 4
and Fig. 5 uses a semi-floating metal 6M which is prepared by changing the position
of the supply opening 61c of the semi-floating metal 6.
[0057] A supply opening 61ca of the semi-floating metal 6M is provide on the side opposite
of the rotating shaft 5 from the housing side supply opening 26. As shown in Fig.
5, the minute foreign matter CT going into the outside oil reservoir space 8b from
the housing side supply opening 26 slips along the outside of the semi-floating metal
6M and is retained at the bottom of the outside oil reservoir space 8b. The supply
opening 61ca of the semi-floating metal 6M is formed at a lower part of the semi-floating
metal 6M. Accordingly, the oil supply path FL goes upward into the inside oil reservoir
space 8a at this part. The oil supply path FL runs relatively close to the retaining
region SA where the minute foreign matter CT is retained. Nonetheless, the oil supply
path FL is designed to pass above the retaining region SA so as not to bring in the
minute foreign matter CT. Furthermore, the flowing direction of the oil supply path
FL is arranged in such a way as to run relatively close to the retaining region SA
and then to go upward into the inside oil reservoir space 8a. Thus, it is possible
to reduce the bringing in of the minute foreign matter CT more effectively.
[0058] Next, a third modified example of the embodiment will be described with reference
to Fig. 6. Fig. 6 is an enlarged cross-sectional view showing the third modified example
of the embodiment depicted in Fig. 2. The modified example shown in Fig. 6 uses a
semi-floating metal 6N which is prepared by changing the position of the supply opening
61c of the semi-floating metal 6, and a bearing housing 2N which is prepared by providing
the bearing housing 2 with a separation wall member 28.
[0059] A supply opening 61cb of the semi-floating metal 6N is provided at a position in
front of the housing side supply opening 26. The bearing housing 2N is provided with
the separation wall member 28. The separation wall member 28 is an L-shaped component
which is provided on the housing inner wall 21. The separation wall member 28 is provided
in such a way as to intervene between the housing side supply opening 26 and the supply
opening 61cb. Accordingly, a separation wall surface 28a of the separation wall member
28 is provided opposite to the housing side supply opening 26.
[0060] The oil going into the outside oil reservoir space 8b from the housing side supply
opening 26 hits the separation wall surface 28a of the separation wall member 28 and
then meanders. Thereafter, the oil hits the outside small diameter portion 61b, which
is the outer peripheral surface of the semi-floating metal 6N, and flows toward the
supply opening 61cb. During this meandering process, the minute foreign matter CT
is separated from the flow of the oil. Accordingly, the removal section RA includes
the separation wall surface 28a. The minute foreign matter CT separated from the flow
of the oil by the removal section RA passes through the conveyance path TA and is
retained in the retaining region SA.
[0061] Next, a fourth modified example of the embodiment will be described with reference
to Fig. 7 and Fig. 8. Fig. 7 is an enlarged cross-sectional view showing the fourth
modified example of the embodiment depicted in Fig. 2. Fig. 8 is a cross-sectional
view showing a B-B cross section in Fig. 7. The modified example shown in Fig. 7 and
Fig. 8 uses a bearing housing 2P which is prepared by changing an internal flow path
in the bearing housing 2.
[0062] A housing side supply opening 26a of the bearing housing 2P is provided opposite
to the supply opening 61c of the semi-floating metal 6. A separation chamber 26r is
formed between the oil feed passage 25 and the housing side supply opening 26a of
the bearing housing 2P. When viewed in the direction of illustration in Fig. 7, an
end portion 25a of the oil feed passage 25 is joined to a portion near the center
of the separation chamber 26r. Meanwhile, the housing side supply opening 26a is joined
to one end portion of the separation chamber 26r. Accordingly, the oil supplied to
the separation chamber 26r hits a bottom surface of the separation chamber 26r, whereby
the flowing direction of the oil is changed. Hence, the oil flows to the housing side
supply opening 26a and then to the supply opening 61c directly. The above-described
flow of the oil defines the oil supply path FL that extends from the oil feed passage
25 to the inside oil reservoir space 8a.
[0063] To be more precise, the oil supplied from the oil feed passage 25 is passed through
the end portion 25a and is supplied to the separation chamber 26r. Since the end portion
25a of the oil feed passage 25 is opposed to the bottom surface of the separation
chamber 26r, the supplied oil hits the bottom surface of the separation chamber 26r
and its flowing direction is changed. Since the separation chamber 26r is filled with
the oil, a main flow of the oil, in which most of the oil flows even though not forming
a fast flow, flows toward the housing side supply opening 26a and the supply opening
61c along the oil supply path FL.
[0064] Meanwhile, the minute foreign matter CT contained in the oil taps into the flow of
the oil and is conveyed from the oil feed passage 25 to the separation chamber 26r.
As described previously, the flowing direction of the oil supplied to the separation
chamber 26r is changed substantially at a right angle along the oil supply path FL.
In this example, the other end of the separation chamber 26r from the one end portion
where the housing side supply opening 26a is formed is joined to the outside oil reservoir
space 8b without using the housing side supply opening 26a (see Fig. 8). The minute
foreign matter CT contained in the oil has a higher specific gravity than the oil.
Accordingly, the minute foreign matter CT does not follow the change in the flowing
direction of the oil but falls along the bottom surface of the separation chamber
26r by inertia. Hence, the minute foreign matter CT moves to the outside oil reservoir
space 8b. Thereafter, the minute foreign matter CT moving downward is retained in
the lower part of the outside oil reservoir space 8b.
[0065] In this modified example, an upper portion of the separation chamber 26r functions
as the removal section RA. As described above, the minute foreign matter CT separated
from the flow of the oil at the upper portion of the separation chamber 26r reaches
the outside oil reservoir space 8b via the separation chamber 26r. Accordingly, a
lower portion of the separation chamber 26r and part of the outside oil reservoir
space 8b collectively function as the conveyance path TA.
[0066] The embodiment of the present invention has been described with reference to specific
examples. It is to be noted, however, that the present invention is not limited only
to these but is defined by the appended claims only.
1. A turbocharger comprising:
a housing (2)
a turbine wheel (31) constituting a turbine (3);
a compressor wheel (41) constituting a compressor (4);
a rotating shaft (5) connecting the turbine wheel (31) and the compressor wheel (41)
to each other, the housing (2) housings at least the rotating shaft (5); and
a semi-floating metal bearing (6) also housed in the housing (2), forming a fluid
bearing between the rotating shaft (5) and the housing (2), and rotatably supporting
the rotating shaft (5), wherein
the semi-floating metal bearing (6) is fixed to the housing (2) by a pin (7),
an oil reservoir space (8b) is formed between the housing (2) and the semi floating
metal bearing (6) to temporarily retain oil,
the housing (2) is provided with an upstream side first supply opening (26) configured
to supply oil to the oil reservoir space (8b), and
the semi-floating metal bearing (6) is provided with a second supply opening (61c,
61ca) configured to supply oil in the oil reservoir space (8b) to an inner bearing
section formed between the semi-floating metal bearing (6) and the rotating shaft
(5),
an oil supply path (FL) extending from inside of the housing (2) to the second supply
opening (61c, 61ca) via the first supply opening (26) is formed to feed oil to be
supplied to the inner bearing section and is provided with a removal section configured
to change a flowing direction of the oil supplied from an upstream side to separate
minute foreign matter in the oil,
wherein the first supply opening (26) and the second supply opening (61c, 61ca) are
located at different positions without being overlapped to each other in an axial
direction of the rotating shaft (5),
characterised in that
the removal section comprises a separation wall surface (61b) formed in an outer peripheral
surface of the semi-floating metal bearing (6), and is opposed to the first supply
opening (26) and to a flow of the oil supplied from the upstream side,
an outer diameter of the outer peripheral surface of the semi-floating metal bearing
(6) is constant from a position opposed to the first supply opening (26) to the second
supply opening (61c, 61ca) and an inner diameter of a housing inner wall (22) is constant
from the first supply opening (26) to a position opposed to the second supply opening
(61c, 61ca);
and a collecting section (TA, SA) is provided to collect the minute foreign matter
(CT) separated by the separation wall surface (61b) so as to prevent the minute foreign
matter (CT) from mixing again with the oil flowing toward the second supply opening
(61c, 61ca).
2. The turbocharger according to claim 1, wherein
the collecting section (TA, SA) comprises:
a retaining region (SA) configured to retain the minute foreign matter (CT) separated
by the separation wall surface (61b) so as to prevent the minute foreign matter (CT)
from mixing again with the oil flowing toward the second supply opening (61c, 61ca);
and
a conveyance path (TA) configured to move the minute foreign matter, separated by
the separation wall surface (61b), from the separation wall surface (61b) to the retaining
region (SA), and
the conveyance path (TA) is joined to the separation wall surface (61b) at a position
different from a main flow path on which the oil flows from the separation wall surface
(61b) toward the second supply opening (61c).
3. The turbocharger according to claim 2, wherein
the retaining region (SA) and the conveyance path (TA) are formed in the oil reservoir
space (8b).
4. The turbocharger according to claim 3, wherein the retaining region (SA) is formed
below the separation wall surface (61b) and the second supply opening (61c, 61ca).
5. The turbocharger according to claim 1, wherein
the second supply opening (61ca) of the semi-floating metal bearing (6) is provided
on an opposite side to the first supply opening (26) across the rotating shaft (5),
and is provided at a position lower than the rotating shaft (5).
1. Turbolader, umfassend:
ein Gehäuse (2),
ein Turbinenlaufrad (31), welches eine Turbine (3) bildet;
ein Kompressor-Laufrad (41), welches einen Kompressor (4) bildet;
eine Drehwelle (5), welche das Turbinenlaufrad (31) und das Kompressor-Laufrad (41)
miteinander verbindet, wobei das Gehäuse (2) mindestens die Drehwelle (5) aufnimmt;
und
ein halbschwimmendes Metalllager (6), welches ebenfalls in dem Gehäuse (2) aufgenommen
ist und welches ein Fluidlager zwischen der Drehwelle (5) und dem Gehäuse (2) bildet
und die Drehwelle (5) drehend lagert, wobei
das halbschwimmende Metalllager (6) an dem Gehäuse (2) durch einen Bolzen (7) befestigt
ist,
ein Ölbehälterraum (8b) zwischen dem Gehäuse (2) und dem halbschwimmenden Metalllager
(6) gebildet ist, um zeitweise Öl aufzunehmen,
das Gehäuse (2) eine erste stromaufwärtige Zuführöffnung (26) aufweist, welche konfiguriert
ist, um Öl dem Ölbehälterraum (8b) zuzuführen, und
das halbschwimmende Metalllager (6) eine zweite Zuführöffnung (61c, 61ca) aufweist,
welche konfiguriert ist, um Öl in dem Ölbehälterraum (8b) einem inneren Lagerabschnitt
zuzuführen, welcher zwischen dem halbschwimmenden Metalllager (6) und der Drehwelle
(5) gebildet ist,
ein Ölzuführweg (FL), welcher sich von innerhalb des Gehäuses (2) zu der zweiten Zuführöffnung
(61c, 61ca) hin über die erste Zuführöffnung (26) erstreckt, gebildet ist, um Öl zu
speisen, welches dem inneren Lagerabschnitt zuzuführen ist, und einen Entnahmeabschnitt
aufweist, welcher konfiguriert ist, um eine Strömungsrichtung des Öls zu verändern,
welches von einer stromaufwärtigen Seite zugeführt wird, um kleinste Fremdstoffe in
dem Öl zu separieren,
wobei
die erste Zuführöffnung (26) und die zweite Zuführöffnung (61c, 61ca) an unterschiedlichen
Stellen angeordnet sind, ohne miteinander in einer Axialrichtung der Drehwelle (5)
überlappt zu sein,
dadurch gekennzeichnet, dass
der Entnahmeabschnitt eine Trennungswandfläche (61b) umfasst, welche in einer äußeren
Umfangsfläche des halbschwimmenden Metalllagers (6) gebildet ist, und welche der ersten
Zuführöffnung (26) und einer Strömung des Öls gegenüberliegt, welches von der stromaufwärtigen
Seite zugeführt wird,
ein Außendurchmesser der äußeren Umfangsfläche des halbschwimmenden Metalllagers (6)
ausgehend von einer Position gegenüber der ersten Zuführöffnung (26) bis zu der zweiten
Zuführöffnung (61c, 61ca) konstant ist und ein Innendurchmesser einer Gehäuseinnenwand
(22) ausgehend von der ersten Zuführöffnung (26) bis zu einer Position gegenüber der
zweiten Zuführöffnung (61c, 61ca) konstant ist;
und ein Sammelabschnitt (TA, SA) bereitgestellt ist, um die kleinsten Fremdstoffe
(CT) zu sammeln, welche durch die Trennungswandfläche (61b) separiert werden, um zu
verhindern, dass die kleinsten Fremdstoffe (CT) sich wieder mit dem Öl mischen, welches
zur zweiten Zuführöffnung (61c, 61ca) strömt.
2. Turbolader nach Anspruch 1, wobei
der Sammelabschnitt (TA, SA) umfasst:
einen Haltebereich (SA), welcher konfiguriert ist, um die kleinsten Fremdstoffe (CT),
welche durch die Trennungswandfläche (61b) getrennt werden, zu halten, um zu verhindern,
dass die kleinsten Fremdstoffe (CT) sich wieder mit dem Öl mischen, welches zur zweiten
Zuführöffnung (61c, 61ca) strömt; und
einen Förderweg (TA), welcher konfiguriert ist, um die kleinsten Fremdstoffe, welche
durch die Trennungswandfläche (61b) getrennt werden, von der Trennungswandfläche (61b)
zu dem Haltebereich (SA) zu bewegen, und
wobei der Förderweg (TA) mit der Trennungswandfläche (61b) an einer Stelle verbunden
ist, welche sich von einem Hauptstromweg unterscheidet, auf welchem das Öl von der
Trennungswandfläche (61b) zu der zweiten Zuführöffnung (61c) strömt.
3. Turbolader nach Anspruch 2, wobei
der Haltebereich (SA) und der Förderweg (TA) in dem Ölbehälterraum (8b) gebildet sind.
4. Turbolader nach Anspruch 3, wobei der Haltebereich (SA) unterhalb der Trennungswandfläche
(61b) und der zweiten Zuführöffnung (61c, 61ca) gebildet ist.
5. Turbolader nach Anspruch 1, wobei
die zweite Zuführöffnung (61ca) des halbschwimmenden Metalllagers (6) auf einer der
ersten Zuführöffnung (26) über die Drehwelle (5) gegenüberliegenden Seite bereitgestellt
ist und an einer Stelle bereitgestellt wird, welche unterhalb der Drehwelle (5) liegt.
1. Turbocompresseur, comprenant :
un carter (2) ;
une roue de turbine (31) constituant une turbine (3) ;
une roue de compresseur (41) constituant un compresseur (4) ;
un arbre rotatif (5) connectant la roue de turbine (31) et la roue de compresseur
(41) l'une à l'autre, le carter (2) recevant au moins l'arbre rotatif (5) ; et
un roulement métallique semi-flottant (6) logé également dans le carter (2), formant
un roulement fluide entre l'arbre rotatif (5) et le carter (2), et supportant de manière
rotative l'arbre rotatif (5), dans lequel :
le roulement métallique semi-flottant (6) est fixé sur le carter (2) par une goupille
(7);
un espace de réservoir d'huile (8b) est formé entre le carter (2) et le roulement
métallique semi-flottant (6) pour retenir temporairement l'huile ;
le carter (2) comporte une première ouverture d'alimentation du côté amont (26) configurée
pour assurer l'alimentation en huile de l'espace de réservoir d'huile (8b); et
le roulement métallique semi-flottant (6) comporte une deuxième ouverture d'alimentation
(61c, 61ca) configurée pour transférer l'huile contenue dans l'espace de réservoir
d'huile (8b) vers une section de roulement interne formée entre le roulement métallique
semi-flottant (6) et l'arbre rotatif (5) ;
un trajet d'alimentation d'huile (FL) s'étendant de l'intérieur du carter (2) vers
la deuxième ouverture d'alimentation (61c, 61ca) à travers la première ouverture d'alimentation
(26), est configuré pour transférer l'huile devant être amenée vers la section de
roulement interne, et comporte une section d'élimination configurée pour changer une
direction d'écoulement de l'huile amenée à partir d'un côté amont pour séparer des
minuscules matières étrangères contenues dans l'huile ;
dans lequel :
la première ouverture d'alimentation (26) et la deuxième ouverture d'alimentation
(61c, 61ca) sont agencées au niveau de positions différentes sans se chevaucher mutuellement
dans une direction axiale de l'arbre rotatif (5) ;
caractérisé en ce que :
la section d'élimination comprend une surface de paroi de séparation (61b) formée
dans une surface périphérique externe du roulement métallique semi-flottant (6) et
est opposée à la première ouverture d'alimentation (26) et à un écoulement de l'huile
amenée à partir du côté amont ;
un diamètre extérieur de la surface périphérique externe du roulement métallique semi-flottant
(6) est constant, d'une position opposée à la première ouverture d'alimentation (26)
vers la deuxième ouverture d'alimentation (61c, 61ca), et un diamètre intérieur d'une
paroi interne du carter (22) est constant de la première ouverture d'alimentation
(26) vers une position opposée à la deuxième ouverture d'alimentation (61c, 61ca)
;
et une section de collecte (TA, SA) sert à collecter les minuscules matières étrangères
(CT) séparées par la surface de paroi de séparation (61b) pour empêcher un nouveau
mélange des minuscules matières étrangères (CT) avec l'huile s'écoulant vers la deuxième
ouverture d'alimentation (61c, 61ca).
2. Turbocompresseur selon la revendication 1, dans lequel :
la section de collecte (TA, SA) comprend :
une région de retenue (SA) configurée pour retenir les minuscules matières étrangères
(CT) séparées par la surface de paroi de séparation (61b) pour empêcher un nouveau
mélange des minuscules matières étrangères (CT) avec l'huile s'écoulant vers la deuxième
ouverture d'alimentation (61c, 61ca) ; et
un trajet de transfert (TA) configuré pour déplacer les minuscules matières étrangères
séparées par la surface de paroi de séparation (61b) de la surface de paroi de séparation
(61b) vers la région de retenue (SA) ; et
le trajet de transfert (TA) est relié à la surface de paroi de séparation (61b) au
niveau d'une position différente d'un trajet d'écoulement principal sur lequel l'huile
s'écoule de la surface de paroi de séparation (61b) vers la deuxième ouverture d'alimentation
(61c).
3. Turbocompresseur selon la revendication 2, dans lequel :
la région de retenue (SA) et le trajet de transfert (TA) sont formés dans l'espace
de réservoir d'huile (8b).
4. Turbocompresseur selon la revendication 3, dans lequel la région de retenue (SA) est
formée au-dessous de la surface de paroi de séparation (61b) et de la deuxième ouverture
d'alimentation (61c, 61ca).
5. Turbocompresseur selon la revendication 1, dans lequel :
la deuxième ouverture d'alimentation (61ca) du roulement métallique semi-flottant
(6) est agencée sur un côté opposé à la première ouverture d'alimentation (26), à
travers l'arbre rotatif (5), et est agencée au niveau d'une position plus basse que
l'arbre rotatif (5).